When recovering hydrogen sulfide from oil sour gas, hydrogen sulfide is usually oxidized to elemental sulfur. One process which can be utilized is based on the use of ferric ions in an alkaline solution and may be represented by the following equation: EQU H.sub.2 S.tbd.HS.sup.- +H.sup.+ EQU HS.sup.- +2 Fe.sup.+++ .fwdarw.S.sup.O +2 Fe.sup.++
After the formation of elemental sulfur, the reduced oxidant, Fe.sup.++, is oxidized by blowing air to Fe.sup.+++.
In one process for recovering sulfur, the sulfur recovery section includes a settling tank and a melter-settler. In the sulfur melting step, oxidant loss, sulfur discoloration and plugging have been observed and are undesirable.
In order to avoid the undesirable consequences of melting the sulfur, it is possible to recover the sulfur by separation from the mother liquor by filtration or centrifugation. However, for such separation techniques to be effective, it is desirable to have a sulfur slurry with a fairly consistent solids content of about 20 weight percent.
During the airblowing step previously mentioned, where Fe.sup.++ is oxidized to Fe.sup.+++, the sulfur and the mother liquid becomes a "froth". Since the flow of hydrogen sulfide into the process is variable, the concentration of sulfur in the froth varies from less than about 1 wt. % to about 20 wt. %. Therefore, what is needed is a method to produce a uniformly consistent concentration of sulfur in a slurry which will settle in a reasonable amount of time in order to avoid the undesirable consequences of melting the sulfur.